Nuprl Lemma : WtoSet-order-preserving
∀[A:Type]. ∀[B:A ⟶ Type].
  ∀x,y:W(A;a.B[a]). ∀b:𝔹.  ((x Wcmp(A;a.B[a];b) y) 
⇒ (WtoSet(a.B[a];x) Wcmp(Type;a.a;b) WtoSet(a.B[a];y)))
Proof
Definitions occuring in Statement : 
WtoSet: WtoSet(a.B[a];x)
, 
Wcmp: Wcmp(A;a.B[a];leq)
, 
W: W(A;a.B[a])
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
infix_ap: x f y
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
infix_ap: x f y
, 
subtype_rel: A ⊆r B
, 
Set: Set{i:l}
, 
all: ∀x:A. B[x]
, 
WtoSet: WtoSet(a.B[a];x)
, 
Wsup: Wsup(a;b)
, 
Wcmp: Wcmp(A;a.B[a];leq)
, 
mk-set: f"(T)
, 
bool: 𝔹
, 
ifthenelse: if b then t else f fi 
, 
exists: ∃x:A. B[x]
Lemmas referenced : 
W-induction, 
all_wf, 
W_wf, 
bool_wf, 
Wcmp_wf, 
WtoSet_wf, 
subtype_rel_self, 
Wsup_wf, 
btrue_wf, 
mk-set_wf, 
bfalse_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
thin, 
instantiate, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
applyEquality, 
hypothesis, 
functionEquality, 
universeEquality, 
because_Cache, 
independent_functionElimination, 
lambdaFormation, 
unionElimination, 
dependent_functionElimination, 
productElimination, 
dependent_pairFormation
Latex:
\mforall{}[A:Type].  \mforall{}[B:A  {}\mrightarrow{}  Type].
    \mforall{}x,y:W(A;a.B[a]).  \mforall{}b:\mBbbB{}.
        ((x  Wcmp(A;a.B[a];b)  y)  {}\mRightarrow{}  (WtoSet(a.B[a];x)  Wcmp(Type;a.a;b)  WtoSet(a.B[a];y)))
Date html generated:
2018_05_22-PM-09_52_07
Last ObjectModification:
2018_05_16-PM-01_31_46
Theory : constructive!set!theory
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